a. Field of the Invention
Sulfur compounds in various forms are known as catalyst poisons in some petroleum processing schemes. Thus, for example, platinum containing catalysts useful for the selective hydrogenation of acetylenes in gaseous hydrocarbon streams are susceptible to sulfur poisoning. Many gaseous hydrocarbon streams are made by the cracking of heavier sulfur containing feedstocks. The gaseous products contain normally gaseous sulfur compounds such as, for example H.sub.2 S, mercaptans and COS. Carbonyl sulfide is a colorless and odorless gas and is always formed when carbon, oxygen and sulfur or their compounds, such as CO, CS.sub.2, and SO.sub.2 are brought together at high temperatures, e.g. 932.degree. to 1652.degree. F. (500.degree. to 900.degree. C.). The complete removal of sulfur compounds such as H.sub.2 S or mercaptans is fairly standardized using amines and/or aqueous solutions of alkali metal hydroxides. Unfortunately the COS is very difficult to remove, for it reacts only slowly with the amines or alkali metal hydroxides. Other techniques are therefore required to effect more efficient COS removal.
B. Description of the Prior Art
U.S. Pat. No. 3,782,076 to Carr et al suggests the use of a supported lead oxide material for reducing the arsenic content of gaseous hydrocarbon streams. While the Diluent Gas No. 3 shown in Column 7, lines 15-28, of the Carr et al patent lists among its components from 0 to 2 ppm of H.sub.2 S and 0 to 5 ppm of COS, there is no teaching in Carr et al that a gas containing COS was for a certainty employed, and there is absolutely no teaching of any kind in the Carr et al patent that even if COS is present, the lead oxide sorbent will serve to remove sulfur compounds of any kind from the gaseous hydrocarbon feedstream.